Prospective Long-Term Followup of Patients With Asymptomatic Lower Pole Caliceal Stones Kubilay Inci,* Ahmet Sahin, Ekrem Islamoglu, Murat T. Eren, Mehmet Bakkaloglu and Haluk Ozen From Faculty of Medicine, Department of Urology, Hacettepe University, Ankara, Turkey Purpose: The intervention time of asymptomatic lower pole calculi remains controversial. In this prospective study we evaluated the natural history and progression rate of asymptomatic lower pole stones. Materials and Methods: Patients were followed every 6 months. Computerized tomography in even years, ultrasound scan in odd years after initial visit and abdominal plain films between these visits were evaluated. The largest diameter was measured for each calculus and the cumulative diameter was calculated for cases of multiple stones. Disease progression was defined as pain experienced during followup, stone growth or the need for intervention. Results: A total of 24 patients, 14 male and 10 female, were followed for a mean of 52.3 months (range 24 to 72). Of the 24 patients 3 had bilateral lower pole stones. Mean cumulative stone diameter at presentation was 8.8 mm (range 2.0 to 26.0). Progression in stone size was demonstrated in 9 of 27 renal units (33.3%) with 2 (11.1%) requiring intervention. There was no need for intervention during the first 2 years of followup. Three stones passed spontaneously without any symptoms. Pain developed in 3 patients during followup, and 2 of them passed a stone and responded to the analgesics without further treatment. None of the patients had a pyelonephritic attack during followup. Conclusions: Our results showed that observation could be considered for patients with asymptomatic lower pole stones. However, patients should be counseled about the 33% disease progression and 11% intervention rates. Key Words: signs and symptoms, urinary calculi, observation I ncreasing stone size, localized obstruction, associated infection and acute or chronic pain are the indications for treatment of lower caliceal stones. 1–3 Because the natural history of small, nonobstructing asymptomatic lower pole calculi is poorly defined and the progression risk is not clear, there is still no consensus on the timing and type of intervention for these stones. Glowacki et al evaluated the natural history of asymptomatic renal stones and reported that the risk of a symptomatic episode or need for interven- tion was approximately 10% per year, with a cumulative 5-year event probability of 48.5%. 4 Recently in a retrospec- tive study 77% of asymptomatic patients with renal stones experienced disease progression with 26% requiring surgical intervention. 5 The most appropriate management of lower pole caliceal stones also remains controversial. ESWL® has low stone- free rates. 6–8 Flexible ureteroscopy is another treatment option with similar stone-free rates for lower pole caliceal calculi 1 cm or less. 9 Percutaneous nephrolithotomy has the highest stone clearance rates but is more invasive. 6,10 In this prospective study we evaluated the natural history and pro- gression rate of asymptomatic lower pole stones, and estab- lished a concept of the best management approach for asymptomatic lower pole stones. MATERIALS AND METHODS The study protocol was approved by the Hacettepe Univer- sity Human Ethics Committee. Any patient diagnosed with asymptomatic single or multiple lower pole caliceal stones for at least 6 months was eligible for inclusion. Patients with a history of treatment for renal stones with pyeloureteral surgery, percutaneous renal surgery or ESWL were also included in the study if they remained symptom-free for at least 6 months. Exclusion criteria were any coexistent stones in other pyelocaliceal locations, history of urinary tract congenital anomalies, solitary kidney, increased serum creatinine (greater than 2 mg/dl), high grade hydronephro- sis, diabetes and pregnancy. Patients were informed about diseases and treatment options in detail, and they were actively involved in the decision making process. Baseline characteristics including patient age, sex, his- tory of urinary tract infection, number of previous stone episodes and most recent stone composition were recorded. All patients underwent a detailed evaluation including non- contrast spiral CT, excretory urography and urinalysis at initial visit. Urine samples (24-hour) were collected on a random dietary regimen to determine volume, oxalate, cal- cium, citrate, uric acid and creatinine. In the first 3 years all patients underwent excretory urography as part of the im- aging protocol. However, this was extracted from the imag- ing protocol at the end of the 3 years. Patients were evalu- ated every 6 months. At each visit a history regarding the development of symptoms, urinary tract infection and he- maturia was taken, physical examination was performed, Submitted for publication October 19, 2006. Study received Hacettepe University Human Ethics Committee approval. * Correspondence: Department of Urology, Faculty of Medicine, Hac- ettepe University, Sihhiye, Ankara 06100 Turkey (telephone: +90 312 3051970; FAX: +90 312 3112262; e-mail: kuinci@hacettepe.edu.tr). 0022-5347/07/1776-2189/0 Vol. 177, 2189-2192, June 2007 THE JOURNAL OF UROLOGY ® Printed in U.S.A. Copyright © 2007 by AMERICAN UROLOGICAL ASSOCIATION DOI:10.1016/j.juro.2007.01.154 2189